There are many known types of recreational vehicles for gliding over snow-covered surfaces. In some types of recreational snow vehicles, such as toboggans, steering is accomplished by selective shifting of the rider's weight, and braking is accomplished by the rider or riders dragging their feet against the snow-covered ground. Other types of snow vehicles include snow sleds having a bicycle-type frame with a pair of fixed rear skis or runners, and a single front ski (or, in some cases, double twin skis) steerably connected to a steering column with handlebars or a steering wheel that is controlled by the rider.
Some snow sleds of this type have no braking mechanisms: see, for example, U.S. Pat. No. 4,168,843 (Hager), U.S. Pat. No. 5,335,925 (Dolson), U.S. Pat. No. 5,580,071 (Yu), and Des. 311,358 (Dallaire). However, a variety of braking mechanisms can be found in other prior art sleds.
U.S. Pat. No. 6,241,265 (Kovar et al.) discloses a snow sled with a bicycle-type frame, twin rear skis, and twin front skis steerable by bicycle-type handlebars. Each front ski is fitted with a spring-mounted metal brake element that can be urged into the snow surface along the side of the ski to slow down the sled. Each brake element is controlled by a cable linkage to a brake lever mounted on the handlebars, in much the same fashion as cable-actuated brakes on bicycles.
U.S. Pat. No. 6,575,479 (Combs) discloses a snow sled with a bicycle-type frame, twin rear skis, and a single front ski steerable by bicycle-type handlebars. Each rear ski has a pivoting brake shoe that can be urged into the snow surface by a cable-actuated brake lever mounted on the handlebars.
The “GT Sno Racer”™ (available from Canadian Tire stores in Canada, and from Northern® Tool & Equipment in Burnsville, Minn.), has a bicycle-type frame, a rider's seat, twin rear skis, and a single front ski steerable by a steering wheel mounted to the frame. This sled has a braking system incorporating a pair of spring-mounted brake pedals mounted below the front portion of the frame. Each brake pedal has a foot rest section, plus a generally planar snow-engaging brake pad that extends both downward and rearward away from the foot rest section. The pedals are mounted to a bracket (or brackets) disposed forward of the pedals. The bracket is suspended beneath the frame so as to be pivotable about a generally horizontal axis. The pedals have biasing means (such as a spring) that will tend to maintain the pedals in a neutral or disengaged position, wherein the brake pads are above the plane of the undersides of the skis.
When the sled is in use, the rider places his or her feet on the corresponding foot rest sections of the brake pedals, with the pedals in the neutral position. When wishing to stop or slow down, the rider exerts foot pressure on the brake pedals, causing the brake pads to pivot forward and be urged into the snow surface over which the sled is moving. This has the effect of slowing the forward movement of the sled, generally in accordance with the amount of force with which the brake pads are urged into the snow surface. When foot pressure on the pedals is relaxed or release, the biasing means pivots the pedals back toward the neutral position.
The prior art sleds described above represent improvements over sleds that do not have braking mechanisms, but they each have disadvantages or shortcomings. The brake elements of the Kovar sled have a narrow profile, and therefore present considerably less resistance (and thus generate considerably less braking force) than the wider brake elements of the Combs sled and the GT Sno Racer™. The braking systems of both the Kovar and Combs sleds are cable-operated, with separate braking elements on skis on each side of the sled. In the event that one of the cables breaks or otherwise becomes inoperative, the sled will have braking on one side only, which can be more dangerous than having no braking at all; e.g., applying braking to one side only to a fast-moving sled may cause the sled to skid out of control due to the lateral offset of the braking force.
This potential problem is eliminated in the GT Sno Racer™, in which the braking force is always essentially aligned with the centerline of the sled. However, with the foot-operated brakes of the GT Sno Racer™, it is difficult to apply small increments of braking force that may be desirable or advantageous for optimal maneuvering of the sled in certain situations, such as when the rider wishes to execute “trick riding” maneuvers. Moreover, the brake pedals of the GT Sno Racer™ are structurally interconnected such that it is difficult or impossible to apply braking force to one pedal without applying some amount braking force to the other pedal, due to the inherent structural stiffness of the brake pedal assembly. This structural arrangement hinders or precludes the use of differential braking techniques which may be desirable for some sled maneuvers.
For the foregoing reasons, there is a need for a snow sled braking system that provides for effective and substantially “centerline” braking for optimal control and stability when rapid or emergency braking is desired, while also facilitating the application of small increments of braking force for enhanced sled maneuverability. There is a further need for braking systems which, in addition to the features described above, also allow differential braking (i.e., independent deployment of separate brake pedals). The present invention is directed to these needs.